Electric heater.



E. THOMSON.

ELECTRIC HEATER.

APrLIoATIoN FILED 1111.18. 1909.

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Patented Nov. 14, 1911.

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vlmesses:

E. THOMSON.

ELECTRIC HEATER.

APPLICATION FILED IAB. 18, 1909.

1,008,622. Patented Nov. 14, 1911.

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Witnesses:

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UNITED STATES PATENT OFFICE.

ELIHU THOMSON` 0F SWAMPSCOTT, MASSACHUSETTS, ASSIGNO i T0 GENERALELECTRIC COMPANY, A CORPORATION OF NEW Y0 RK.

ELECTRIC HEATER.

Specification of Letters latent.

Patent ed Nov. 14, 1911.

To all wwm it may concern.'

Be it known that I, ELIHU THOMSON, a citizen of the United States,residing at Swainpscott, in the county 0f Essex, State of Massachusetts,have invented certain new and useful Improven'ients in Electric Heaters,of which the following is a specification.

This invention relates to electric heaters and the like andlias for itsobject the provision of a device of this character in which the energyof an electric circuit is transformed into heat by means of relativelymoving parts, as for instance, by means of an electric motor or similarapparatus.

In the use of electric heaters difliculty has been experienced in theinsulation of the conductor, if the heater is operated at a relativelyhigh temperature. This is especially so where high voltages are used,say,

, for instance, 500 volts.

One of the objects of my invention, therefore, is to produce an electricheater which will run at a comparatively high temperature, theconditions being somewhat similar in an electric locomotive.

In carrying out my invention I enipcy a device in which the heat is notgenerat in the copper conductors and the necessit for extra insulationof the conductors ist ereby avoided. By the use of an electric motoroperated at the greatest possible ineiiiciency, I am able to brin aboutthis result. The motor is operatedg at high speed and the armature ironof the motor is short cirfi: eluted, either by using a non-laminatedcor'e4 of ood conductivitas for instance, soft stec or a material o hi hhysteresis may be used to increase the` eilgect I so construct the motorthat the armature Vis stationary and a field rotates within thearmature, though the reverse might be used, but` would demand packedsteamandwater joints, a manifest disadvantage. j

Passages are provided within the solid core ofthe armature, or in a massin directiheat conductive relation therewith for the circulation offluid to be heated, and a pum may be arranged to bedriven in any esired'manner to circulate the water through the passages except when thecirculation would e automatic, as in some steam and hot water systems.The armature is preferably heat insulated from the field, so that noconsiderable heat is tran smitted thereto and a heat insulation likewi;e covers the armature. The windings o: the armature are preferablylikewise heat insulated from the core to prevent them fro n beingoverheated. The eommutator is best .nounted so as to be independent ofthe core, so that all the heat which is developed is re stricted to thecore and to the water which :s circulated to take it up for usefuldistribu ion. Other objects of my invention will apr ear in the courseof the following specificatii 1n, in which I have shown my invention enbodied in concrete form for the purposes o. illustration.

In the accompanying lrawings, in which I liave shown one forn, of myinvention, Figure 1 represents a se :tional elevation of my device; Fig.2 represents a section on the line 2-2 of Fig. 1; Iig. 3 represents thearrangement of the mo :or in the heating system; and Figs. 4 and 5 arediagrams of the circuit connections o? different types of motors.

Referring to the dra ings, 10 represents the rotating member of themotor, which in this case is the field of tl .e motor; 11 represents theannular armatu re surrounding the iield. This armature co1 sists of anannular core'12 having a spiral passage 13 inclosed the core of solidiron oi steel of comparatively good conductivity Instead of laminatingit, as is generally tie case where the motors are to e run for ordinarypurposes. The iron may be chosen as having a high hysteresis, inwhichcase the conductivity is not so important. The irmature hasconductors 14 mounted on tt e inner face of the core, or within slotsinsuch face and heat insulated both from the core and the rotatablefield by means of an insulatingmaterial 15, such as asbestos or thelike. The

rejecting ends of the w: riding need not be insulated for heat exceptfrom the armature iron. They can be expoied to air circulation. The coreis likew isc lagged on the outside with heat insulatf ng material 16, soas Eto prevent the heat-co ivection and radiation into theI air. n thctop of the core is mounted a bracket 17, which is provided at 18 with abcarin for the shaft of thc rotating field. Brusles 19 are mounted onthe collar 20 and are pressed into contact with the commutator bysprings 21. Collector rings 22 are rigidly secured to the shaft 23 so asto rotate therewith. The commutator bars 424: are arranged to form aring, as shown, on the inside of the bracket and are insulated from thebracket. The windings of the armature are connected to the commutatorsegments by conductors 25. Brushes 26 engage the rings 22 and arerigidly mounted on the bracket in any well known manner. sh'own, fourpole pieces, and the winding 27 is connected up as shown in the diagramin Fig. 4, but the machine may be bipolar or multipolar as desired.

The motor which has just been described is connected into the heatingsystem in the manner shown in Fig. 3, by a ump 28 of any desired type,driven in any esired way, as for instance, by the motor itself, whichcauses the circulation of the fluid to be heated through the coils 13and the core, or the circulation may be automatic -in some cases.Radiators 29 may be connected as shown with the upper end of thecirculating tube and may be for hot water or steam, dependent upon theconditions desired. A tank 30 is arranged to act as a hot well fromwhich the way the uld is kept in circu ation through the core. Radiatorsmay be'arranged at various points throughout the car or other room whichit is desired to heat.

In Fig. 4 I have-shown the circuit con- 40 nections. One of the brushes26, which is indicated by 26, is connected to the positive mainthrough'rheostat R; brush 26" is connected to the negative main, and thethird brush, 26, is connected directly t the ositive main. The ring- 19,engaged by rush 26, is connected toone set o tator bars, while ring 19,which is engaged by brush26", is connected with the other set ofcommutator bars. Ring 19, which is enaged by brush 26, is' connectedwith the eld circuit. sible to excite e field before throwing on theamature current, and a starting resistance at R ma In Fig. 5 have showna' machine connected as a series machine, in which case it cannot runaway from lack of load owing to the work done in the unlaminated hstereticiron .core of the armature. In is e0 case but'two sli rings areneeded, 31 and 32, engaged by rushes '33 and 34, respectively. 'nectedwith the ring 31 while the other is connected with the ring 32. Thebrush 33 66 is connected .with one of the commutator The field of themotor has, as

pump takes its su ply. In 'this' iron core having passa es therethrou hfor Irounding said windin therefrom, heat insulation surrounding commu-4 field windintg consisting o Asa es therethrough for the circulation ofa jfluid to be heated, and suitable windings lheat insulated from thecore.

Bty this arrangement it is posbe used to start the motor. v

heat insulated the ne end'of the field winding is conbrushes 19 whilethe brush 34 isconncctcd with one side of the lin'c through the rheostatR, the other side of the line heilig connccted with the other commutatorbrush 19.

It will bc soon that l have provided an 70 electric heater in which theelectric conductors themselves are not used as the heating current. Thecore of the armature does the heating by reason of the eddy current andhysteresis loss therein. It should be understood, of course, that thearrangement that I have above disclosed is merely typical and may bevaried without departing from the spirit of my invention, the scope ofwhich is set forth, in the annexed claims.

What I claim as new and desire tosecure by Letters Patent of the UnitedStates, is-- 1. An electric heater comprising a hi h speed electricmotor having a rotating lie d magnet and a stationary armatureconsisting of a solid iron core .having assagestherethrough for thecirculation o a uid to be heated, and an armature winding on said coreand heat insulated therefrom for producing rotation of said ield magnetand thereby generating eddy currentsv to heat said core. v

2. An electric heater comprising a hi h speed electric motor having arotary d magnet and a stationary armature consisting of a shortcircuited iron core with passa es therethrough for the circulation of aHuid to be heated, a' winding on said core for producing rotation ofsaid eld magnet and thereby generating eddy currents to heat said core.4

3. An electric heater'comprising 'an armature consisting ofsuitablewindings, a solid- Hui to be heate surand heat insulated said core and aield winding' rotatably mounted within said armature windi vit. Anelectric heater comprising a rotary and a'stational amature I o l a'sohdiron core vlng pasthe circulation o 5. An electric heater comprising arotary fieldI windin and a stationar armature consisting o a solid ironcore aving passages therethrou h for the circulation of a iiuld to beheatedg, suitable windin heat insulated vfrom thecore, and heatmsulationsurrounding said core.

6. An electric heater 'comprising an armature consisting of suitable wina solid iron core -surroundin said win gs and rom, heat insulationsurrounding said core, and a field winding rotatably' mounted withinsaid armature windmg. l

7. An electric heater comprlsing an arma- 130 ture consisting ofsuitable windings, a solid In witness whereof, I hav e hereunto setixllon corelhavmg Passages therethrou h for my hand this 16th day of March, 1909.

t e cil-cu ation o Huid to be heate sur- Y rounding said Winding andheat insulated ELIHU PHQMSON' therefrom, heat insulation surroundingsaid n Witnesses:

core, and a eld winding rotatably mounted ROBERT SHAND,

within said armature wlnding. CHARLES A. BARNABD.

